CHICAGO - China's Wanxiang Group Corp beat other bidders Saturday to win the auction of bankrupt US battery-maker A123 Systems for a price of about $250 million, the company said.

Wanxiang, a Chinese auto-parts maker with its North American headquarters in Elgin, Illinois, fended off a joint bid of Johnson Controls Inc of Milwaukee and NEC Corp of Japan after a day-long auction.

But Wanxiang excluded US government and military contracts with the battery maker from its purchase, while Navitas Systems, a spinoff of MicroSum Technologies, got those "sensitive parts."

Pin Ni, president of Wanxiang's US arm, said his company would nurture A123 over the long haul, absorbing losses for five or 10 years if necessary.

A123's board met Saturday and was expected to approve the transaction. CFIUS, a government body led by Treasury Secretary Timothy Geithner, should also approve the transaction.

Wanxiang's purchase of A123 marks the second major foreign purchase of a US battery company funded by the US Department of Energy.